1. Internal leakage of hydraulic cylinder. Hydraulic cylinder internal leakage includes hydraulic cylinder body seal, piston rod and sealing cover seal and piston seal all wear excessive leakage. The reason for leakage of piston rod and sealing cover is that the sealing parts are corrugated, extruded, torn, worn, aged, deteriorated and deformed. At this time, new sealing parts should be replaced. Excessive wear of piston seal is mainly caused by improper regulation of speed control valve, high back pressure, improper installation of sealing parts or hydraulic oil pollution. Foreign body entering and sealing material quality is not good. The result is slow movement, weak, serious when it still can cause piston and cylinder damage, appear "pull cylinder" phenomenon. The treatment method is to adjust the speed control valve and make necessary operation and improvement according to the installation instructions. Cleaning the filter or replacing the filter core, hydraulic oil.

2. Leakage of hydraulic circuit. It includes leakage of valves and hydraulic piping. The repair method is to control the reversing valve to check and eliminate the leakage of the hydraulic connection pipeline.

3. The hydraulic oil passes through the overflow valve and returns to the oil tank. If the overflow valve enters the dirt to jam the valve core, making the overflow valve open normally, the hydraulic oil will flow directly back to the oil tank through the overflow valve bypass, resulting in no oil entering the hydraulic cylinder. If the load is too large, the regulating pressure of the overflow valve has reached the maximum rating, but the hydraulic cylinder still does not get the thrust required for continuous action and does not move. If the adjustment pressure is low, the pressure is insufficient to reach the required vertebral force, which is shown as insufficient thrust. Checking and adjusting the overflow valve at this time.